Type IS machines for the manufacture of glassware articles are well known and have been widely used in the industry for a many years. It is also well known that such machines require the employment of an arm for transferring the parison, which is the intermediate shape produced in the manufacture of a glass article in more than one step, while being formed in a preforming station, transporting the parison to a blowmolding station, for which purpose a system means is provided for rotating the arm and reversing its position in such a way that the parison is inverted in the preform station, the parison being supported at the neck thereof by a crown fixed to the reversing arm whereby the parison reaches the blow molding station in an upstanding position in order to permit the two halves of the blowmold to close to terminate the operation of forming the glassware article.
The reversing mechanism of the type IS machine previously described includes an arm which rotates in the manner indicated to convey the parison from the preform station to the blow molding station and consequently upon reception of an adequate signal, to reverse the original position of the arm for reception of a new parison.
The movement of the reversing arm, both in the reversing movement which is critical, and in its reversing movement which is not critical inasmuch as in the latter movement the arm and its crown are empty, the movements thereof have been generally controlled only by the reception of a reversing starting signal, with no allowance or provisions being made use of or by adequate equation to avoid abrupt acceleration or deceleration which distorts the parison and makes it difficult to achieve a well formed product by blow molding. Also, such present day mechanisms in their reversing movement tend to impact at the end of such movement, that is, at its terminal position in the molding station, said impact seriously distorting the conveyed parison, damaging the mechanism, which in time makes it necessary to replace or adjust same.
Furthermore, although the reversing arm and crown in reversing movement may not be carrying a preform, the possibility of impact of the mechanism with the attendant damage or wear still exists thus shortening considerably the life of the mechanism.
The reversing mechanism of present day type IS machines is generally controlled by means of the well known timing drum which sends inverting and reversing signals at predetermined intervals in accordance with the type of article being manufactured in the machine, and thereby requiring the well known procedure of inserting cams in adequate positions on the timing drum, said cams operating pneumatic valves for transmitting signals to other pneumatic valves timed to operate the mechanism by fluid actuators.
Although electronic timing controls have been previously employed for operating machines for glassware forming, such electronic controls replaced the traditional timing drums and the inverting and reversing signals were transmitted by electronic timing controls to pneumatic valves or solenoid actuated valves operating the reversing mechanism for either inverting or reversing movement, without absolute control of said movement to prevent impact action of the mechanism and excessive acceleration and deceleration of the same, thus causing damage to the parison during inverting movement, and thereby affecting the quality of the final product, and simultaneously causing damage and/or wear of the mechanism because of improper deceleration by use of a control signal, rather than by employing a braking action when in a predetermined position. This has not eliminated the acceleration and deceleration and resultant impact forces.
Therefore, it is our contention that the control systems of past technology in this art have been quite inefficient, as operation of said systems did not result in a high quality glassware article nor in longer life of the mechanism.
The type IS machine for manufacturing glassware articles on the other hand, requires a take-out mechanism which removes the formed glassware article from the blow molding station prior to the opening of said mold, to carry the finished article to a dead plate on which the glass article cools and which is being transferred by an impulsing mechanism to a conveyer belt which will transport it to the next treatment station, as for example to an annealing furnace.
The takeout mechanism of the type IS machine heretofore described, includes an arm which pivots in a form similar to the arm previously mentioned with the difference that the takeout arm is provided with gripping mechanism to hold the neck of the glassware article formed by blowing, said gripping mechanism being synchronized with the movement of the takeout arm in order to pneumatically close the gripping mechanism about the neck of glassware articles carried by the forming station, thus enabling the takeout arm to swing with the glassware article until it is deposited on the dead plate which is adapted to cause the gripping mechanism to open pneumatically for releasing the glassware article and return the empty takeout arm and move it to the forming station preparatory to engaging another glassware article for repetition of the cycle.
The takeout mechanism of type IS machines is also controlled by means of the well known timing drum which is adapted to transmit takeout engage and takeout disengage signals at predetermined times according to the type of glassware articles being formed, the gripping mechanism being controlled in its open and closed position by a separate set of cams on the aforementioned timing drum in order to transport the glassware article from the forming station to the dead plate, and then by means of an adequate signal the takeout arm is reversed to return to the forming station for reception of another glassware article.
Movement of the takeout arm for conveying the article from the forming station to the dead plate is also very critical and should be performed by following the predetermined viscoelastic equation which eliminates breakage or distortion, while the mechanism tends to impact at the extremes of movement, as in the case of the inverting mechanism previously described.
These movements have not been controlled in prior art devices by application of the adequate viscoelastic equation, and the electronic control systems employed up to the present date employ only the timing drums, whereby the previous problems encountered relative to takeout mechanisms are quite similar to those described for inverting mechanisms for type IS machines for manufacturing glassware articles. Thus, all of the control systems for takeout mechanisms for type IS machines of the former technology have been very inefficient as to their effective operation toward achieving a high quality and low percentage of breakage of glassware articles produced, and at the same time achieving longer life of the mechanism.